With the rapid expansion of the market for laptop computers, mobile phones and electric vehicles, demand for secondary batteries with high energy density is growing. The means for providing secondary batteries with high energy density that are currently being developed include, for example, a method using a negative electrode material having a large capacity, and a method using a positive electrode having a high electrical potential. In many cases, the voltages of general lithium ion secondary batteries are in the range of from 3.5 to 4.2 V. However, lithium ion secondary batteries with positive electrode having a high electrical potential have a voltage of 4.5 V or more; therefore, it is expected that the energy density of such lithium ion secondary batteries will be improved. It is also conceivable that the use of such a positive electrode in combination with a negative electrode having a larger capacity will further enhance the increase of the capacity of the batteries.
However, the use of a positive electrode having a high electrical potential leads to a problem of deterioration of battery performance due to the decomposition of an electrolytic liquid. As a method for suppressing the decomposition of the electrolytic liquid, for example, Patent Document 1 discloses a method in which an aliphatic compound having 1-propenyloxy group or the like is added to the electrolytic liquid.